ga362: Never and I mean NEVER turn in found cash to the police. You might as well give it to charity. The rightful owner will probably never see the cash.And Never return a lost wallet to the owner. Mail it to them unless you want to be accused of taking any cash that happened to be in there. Or any cash the owner alledges to be in there.

/experience speaking

Keeping found cash is a crime; you can go to jail for it. The proper procedure is to turn it over to the police and, if it is not claimed within a specified amount of time, it is returned to the finder. If you return a found wallet to the owner , you cannot be accused of taking any cash missing, since the owner cannot prove that their was any cash in the wallet with it was lost. I've done this twice; once the owner told me I should have kept the hundred bucks in it as a reward. The other just thanked me profusely and offered me a reward.

It never pays to be a dick to other people.

Somehow I don't consider mailing a persons wallet and cash to them anonymously is being a "dick".